The present invention relates to an engine simulation apparatus. In particular, the present invention relates to a Turbofan Propulsion Simulator (TPS).
Such engine simulation apparatuses and/or TPS apparatuses are generally used in wind tunnel models in order to simulate the actual and/or real engine performance characteristics. ATPS apparatus usually has an engine powered by compressed air, which provides the required amount of air within a short period of time for driving the engine. The aerodynamic characteristics of the engine, that is for example the engine pressure ratio and the mass flow, should be substantially the same as those of an original engine that is to be simulated.
Because compressed air is used to drive the engine and/or the turbine instead of a compressor and a burning chamber in front of the turbine, a corestream is not correctly represented, i.e. with regard to temperature and mass flow. However, in order to arrive at a good simulation of the original engine, it is necessary to reach the same jet outlet mach number in the core stream. Further, it is important to reduce the mass flow to a minimum. Therefore, different TPS apparatuses exist for a plurality of wind tunnel models with a defined scaling for different model scales.
Until now, each TPS apparatus has been designed for a specific operating point and/or a specific engine having a specific size. The driving turbine therein is designed for an operating point of a specific turbine. The entire design of such an apparatus is therefore very compact and complex. Furthermore, a very complex oil lubrication, a very specific sealing system and a carefully designed bearing system are required, which due to the high loads and rotational speeds, for example, of up to 80.000 RPM, are to be taken account of for such a small apparatus as for example shown in FIG. 14 hereinafter.
Further, an exact dynamic calculation and an adaptation of the natural bending frequencies of the entire rotor system are required. Therefore, the main housing comprising the turbine, the shaft and the bearing installations is a very expensive part. Furthermore, it is the part that requires the most time during design and/or development, production and assembly. The total cost for the development and production of a new apparatus are very costly and account for a period of time of approximately two years.
Moreover, there is currently the requirement that new engine simulation apparatuses and/or TPS apparatuses for a new turbine generation are developed and produced, which account for very large bypass ratios that for example cater for a passenger aircraft of the type Airbus A350, and can also thought to be used in new short distance aircraft. Known TPS apparatuses do not display the required aerodynamic characteristics of a fan means to simulate this new turbine generation, including the characteristics of engine performance and engine size.
Further, in the document AIAA 94-2554 “Next Generation Propulsion Simulation Equipment for Use in Wind Tunnels” by B.C. Camp from the 18th AIAA Aerospace Ground Testing Conference, Jun. 20-23, 1994 in Colorado Springs generally describes to use an available TPS apparatus and to provide the same with different fan means in order to carry out the engine simulation. Only retrofitting of an available TPS apparatus has however the disadvantage that engine simulation experiments can only be done on the basis of predefined settings and operating parameters of the TPS apparatus. Such an available TPS apparatus is, however, not meant to nor configured to simulate new engine generations. In particular, a turbine unit of an available, old engine of a manufacturer is usually a type of blackbox. That means one usually does not know the inner details in order to, for example, carry out a rotor dynamics calculation or the like. Further, there is a great number of such old engines, which are all not suitable for future wind tunnel tests, because the fan performance does not suit modern engines. Retrofitting old, available engines with a new fan means representing nowadays engines would prevent new developments. Since there are many old engines of different size, one can with relatively small means provide a completely new engine family, which modularly complement one another and cover the entire size and performance range.
One objective of the present invention is therefore to provide an approved engine simulation apparatus and an improved method for engine simulation.